Even with the wide spread use of an electronic document, a printed document is still used especially for a meeting as the printed document is easier to read or write, or easier to carry, when compared to the electronic document. Such printed document to be distributed at the meeting may contain confidential information such that the printed document needs to be protected.
Various methods of preventing the leakage of confidential information from the printed document have been introduced. For example, the printed document having confidential information may be embedded with a specific pattern. When a user instructs an image forming apparatus to copy the printed document, the apparatus stops copying of the printed document if the specific pattern is detected. While copying of the printed document may be prevented, this technique is not capable of preventing the leakage of the printed document itself.
In order to prevent the leakage of the printed document itself, the printed document, which has been distributed at the meeting, may be managed, for example, by assigning a specific number to the printed document. Since the printed document is usually distributed to each one of a large number of meeting attendants, managing each printed document distributed to each attendant is cumbersome. Further, when the printed document includes a large number of pages, managing all pages for each printed document for each attendant becomes even more difficult.
Japanese Patent Application Publication No. 1-108-241309 describes a technique of adding distribution destination information to a document to be printed for distribution. While this may help the printed document to be managed more easily, it does not prevent the leakage of the printed document as it is difficult to mange the printed document itself once the printed document is distributed to each attendant.
Japanese Patent Application Publication No. 2008-65550 describes a technique of concealing confidential information contained in a document to be output. While this may conceal the confidential information contained in the document, conceal processing and output processing needs to be performed for each document and for each destination, one by one, such that preparation of such document may be time consuming especially when preparing a large number of documents for a large number of meeting attendants.